你会想INotifyPropertyChanged
用你的类来实现C
。在 的集合中ValueOfC
,您将触发事件:
class C : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private int valueOfC;
public int ValueOfC
{
get { return valueOfC; }
set
{
valueOfC = value;
OnPropertyChanged(PropertyChanged);
}
}
protected virtual void OnPropertyChanged(PropertyChangedEventHandler handler)
{
if (handler != null)
handler(this, new PropertyChangedEventArgs("ValueOfC"));
}
}
我刚刚测试了它,它工作得很好。
让受保护的虚拟方法为您触发事件只是常见做法。
附带说明一下,如果您想在列表发生变化时做某事,您可能需要考虑使用BindingList或ObservableCollection。
编辑
我写了一个小例子来刷新整个树:
public class Bank : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private BindingList<Customer> customers = new BindingList<Customer>();
public int Worth
{
get { return customers.Sum(cust => cust.FullBalance); }
}
public Bank()
{
customers.ListChanged += new ListChangedEventHandler(customers_ListChanged);
}
void customers_ListChanged(object sender, ListChangedEventArgs e)
{
Console.WriteLine("A customer has changed.");
var handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs("Worth"));
}
public void Add(Customer c) { customers.Add(c); }
}
public class Customer : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private BindingList<Account> accounts = new BindingList<Account>();
public int FullBalance
{
get { return accounts.Sum(acc => acc.Balance); }
}
public Customer()
{
accounts.ListChanged += new ListChangedEventHandler(accounts_ListChanged);
}
void accounts_ListChanged(object sender, ListChangedEventArgs e)
{
Console.WriteLine("An account has changed.");
var handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs("FullBalance"));
}
public void Add(Account a) { accounts.Add(a); }
}
public class Account : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private int balance = 0;
public int Balance
{
get { return balance; }
set
{
var handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs("Balance"));
}
}
}
class Program
{
static void Main(string[] args)
{
Account a1 = new Account() { Balance = 5 };
Account a2 = new Account() { Balance = 10 };
Account a3 = new Account() { Balance = 15 };
Customer c1 = new Customer(); c1.Add(a1); c1.Add(a2);
Customer c2 = new Customer(); c2.Add(a3);
Bank b = new Bank(); b.Add(c1); b.Add(c2);
Console.WriteLine();
a1.Balance += 100;
}
}
现在您可以if (e.ListChangedType == ListChangedType.ItemChanged)
在事件处理程序中编写类似的内容,或类似的内容。